γνωτοκτόνος

From LSJ

ἔνδον γὰρ ἁνὴρ ἄρτι τυγχάνει, κάρα στάζων ἱδρῶτι καὶ χέρας ξιφοκτόνους → yes, the man is now inside, his face and hands that have slaughtered with the sword dripping with sweat

Source

Spanish (DGE)

-ον fratricida παλάμη Eudoc.Cypr.1.39.